Center lap



Patented Nov. 29, 1949 UNITED STATES PATENT OFFICE Application April 15,

8 Claims. (01. 51-185) This invention more particularly to a lathecenter lap having a replaceable abradant surface stratum. Initiachineoperations upon work pieces having therein preformed lathe centers orconical depressions usually of sixty degrees contour, such conformationsbecome coated with foreign material, rust or dirt deposits whichdestroys the accuracy with which such parts may be mounted for furthermachining operations. The deposit of scale within the conical centers ofparts which may have been heat treated is especially prevalent. Thepresent abrasive center lap is especially designed for removing suchdeposits and for reducing the conical center depressions to accurateform and polishing the interior surfaces thereof, Heretofore abrasivewheels or stones which require more or less frequent dressing orroughing have been employed for this purpose. Repeated dressing thereofeventually changes the shape and size of such permanent laps.

To enable successive centers to be uniformly surfaced it is desirable touse a fresh abrasive surface for each operation. ln the present instanceprovision is made for quickly engaging with a holder and releasinginterchangeable abrasive coated cones which conform to the angularity ofthe center depressions of the work pieces.

The object of the invention is to improve the construction as well asthe means and mode of operation of abrasive center laps whereby they maynot only be economically manufactured, but will be more eflicient inuse, rapid and accurate in operation, uniform in action, and unlikely toget out of repair. i

A further object of the invention is to provide interchangeable abrasivecones which conform to the conical center depressions'to be cleaned.

A further object is to provide an improved reinforced construction ofthe abrasive cones, and to provide an unaligned seam to insuresmoothness of operation and prevent injury of the cone.

A further object of the invention is to provide an improved holder ormount with which the abrasive cones may be easily and quickly engagedand disengaged.

A further object of the invention is to enable the use of a freshabrasive surface for each operation and to obviate thenecessity ofdressing the abradant surface and hence assure maintenance of accuratesize and shape thereof.

A further object of the invention is to provide an abradant center laphaving the advantageous structural features, the inherent meritoriouspertains to abrading tools and characteristics and mode of operationherein set forth, or their equivalents. D With the above primary andother incidental objects in view as will more fully appear in thespecifications, the invention intended to be protected by Letters Patentconsists of the features of construction, the parts and combinationsthereof, and the mode of operation, or their equivalents, as hereinafterdescribed or illustrated in the accompanying drawings.

Referring to the drawings wherein is shown the preferred, but notnecessarily the only form of embodiment of the invention,

, Fig. l is a perspective ,view of an assembled center lap embodyingthe-present invention together with a portion of -a work piece havingtherein a conical center depressionto be cleaned.

Fig. 2 is a side elevation, partly insection of the centerv lap shown inFig. 1. Figs. 3 and 4 are reverse perspective views of an abrasive coneremovedfrom its holder.

. Fig. 5 is a plan view, somewhat diagrammatic, of the abrasive coneblank before formation.

Fig. 6 is a plan view of a blank for the cone reinforcement liner.

Like parts are indicated by similar characters of reference throughoutthe several views.

Referring to the drawings, l is a portion of a. work piece having in theend thereof a preformed conical lathe center depression 2 which thepresent center lap is adapted to clean and polish.

The center lap, forming the subject matter hereof, shown in Figs. 1 and2, comprises a cylindrical body portion 3 reduced at one end to aconical terminal 4 of shape and size to fit the center depression 2. Theterminal 4 is preferably of approximately sixty degrees angularity,which is the established standard. At its opposite end the body 3 isprovided with an axial shank or stem 5 engageablein any lathe or drillpress chuck, or in a lathe tail stock. It may be used in a hand drill ora brace. Slidingly mounted on the cylindrical body; is a clamp sleeve 5,one end of which is angularly flanged internally at 1 to agree with thetapered terminal 4. :-Interchahgeablyengageable over the conicalterminal 4 are a series of'abrasive coated caps or cones 8-8. The coneso'r caps 8- are formed from abrasive coated sheet material, and arewrapped and pressed over a corresponding form or mold. They have analtitude sufficient that when positioned over the conical terminal 4 ofthe holder, the base margin of the cone will be overlapped and clampedby the inclined flange 1 of the sleeve 5 upon partial rotation of thelatter.

The sleeve 6 is provided at its opposite end with a bayonet slot 9, thetransverse arm of which is slightly inclined to afford cammingengagement with a stud l0 projecting from the main .body 3 by which theflange 1 is caused to grip the margin of the cone under pressure. Thecone 8 after use is easily and quickly disengaged by a reverse. partialrotation of the sleeve 6.

The blank from which the abrasive cap or cone 8 is formed comprises asegment of one hundred and eighty degrees. The transverse margin thereofis of undulating form, as shown in Fig. :5 The radii of the ogeemarginal curve of the blank is equal to the radius of blank. The ogeeshape of the margin insures that, the seam ll of the finished cone iscurved, which during rotation passes a given point on the work in anoblique direction, cutting action without chatter and without in-' juryto the cone. Interiorly attached to the cone is an adhesive semicircularliner l2 of gum-med paper or the like. The liner i2 is 'attachedi .611relation that it extends across the curved seam H and the joint or seamof the liner I2 is positioned diametrically opposite the curved abrasivecone. The abrasive and liner blanks are wrapped and formed upon -acorrespondingly shaped mandrel or within a mold, as a separate articleof manufacture for interchangeable use with the holder. Theabrasive-caps or cones are preferably coated with grit of differentdegrees of coarseness. The 100, 120 and 150 grades of grit are mostpopularand preferable. The cones may be used repeatedly until theabrasive surface is exhausted before changing cones.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modificationin its form, proportions, detailconstruction vandar rangement of parts without departing from "theprinciple involved or sacrificing any of its -advan-' tages.

While in order to invention has been described in language -more or lessspecific as to-structural features, it is to be understood that theinvention is not limitedto the specific features shown, but that themeans and construction herein disclosed comprise the pres ferred form ofseveral modes of put-ting the-invention into effect, and the inventionis therefore claimed in any of its forms or modifications with! in thelegitimate and valid scope of the appended claims.

Having thus, described my invention, I claim:

-1 A center lap, including a one piececyli-ndria .calbody, a conicalhead at the segmental arc of the 7 seam u of-the;

comply with the statute the able-abrasive conical cap-conforming to theconical head. means position fitted to for securing the conical cap inthe conical head, said cap comprising a semicircular segment of abrasivesheet thus insuring smooth even {rolled upon itself portions :of itsogee material having an ogee transverse margin, with the reversecurvilinear margin in abutting relation, and an adhesive liner for thecap.

4. As an article of manufacture, a conical abrasive surfaced capcomprising a semicircular segment of abrasive sheetmaterial having anogee transverse margin, rolled upon itself with the reversely curvedportions of the ogee margin in 'ajbutting relation forming a curvilinearjoint extending from the apex to the base of the conical cap.

' 5. As an article of manufacture, comprising 7 in one side of theconical cap extending from its apex to its base.

of manufacture, a hollow conical abrasive surfaced cone, a joint in oneside thereof and an adhesive liner therefor transversely of the interiorof the joint.

7. As an article of manufacture, a hollow abrasive surfaced cone, ajoint in one side thereof extending approximately from its apex to its"base, and a correspondingly shaped adhesive of the abrasive surfacedcone. 8. {is an article of manufacture a hollow abrasive surfaced cone,a curvilinear JULIUS R. REICH.

REFERENCES CITED UNITED STATES PATENTS of record in the Number Name Date170,178. Locke Nov. 23, 1875 1.1420 muidine June 3.. 1915 1,646,330 Talor Oct. 18., 1922 1,397,495 Perriera et a1. Feb. 14, 1933 2. 26.051 Lot .Dec- 3 ,1935 ammo fie1d.- .T.- .-..-=e-- N 2 4 ormer PATE T iliambsr'Countr Date Q 17.1.18? 7 Switzerland g. 1, 1934

